Electrochemical characteristics of graphene/manganese oxide composite catalyst for Li-oxygen rechargeable batteries

Graphene/MnO2 composite was obtained by hydrothermal oxidation of the Mn-precursor on a graphene surface. The composite showed a fine dispersion of MnO2 nanorods over graphene nanosheets (GNs). The addition of MnO2 to GNs accelerated the oxygen reduction in the cathodes of Li-O2 cells and promoted Li2O2 catalysis efficiently, compared with the pristine GNs. The power densities of the composite and the pristine GNs were 13.27 and 9.72 mW cm−2, respectively. In addition, the cell containing GNs/MnO2 electrode exhibited stable cyclic performance.